Answer:
A
Step-by-step explanation:
Mechanical energy (ME) is Kinetic energy + potential energy
Where
Kinetic Energy (KE) = 1/2 * m * v^2
where m is the mass (in kg) and v is the speed of the object (in m/s)
and
Potential Energy (PE) = m*g*h
Where m is the mass (in kg) and g is the gravitational constant (9.81 m/s) and h is the height (in meters)
Hence
ME = KE + PE (note the pendulum DOES NOT have any speed, so v = 0, and thus KE = 0)
So,
[tex]ME=KE+PE\\ME=\frac{1}{2}mv^2+mgh\\ME=\frac{1}{2}(1)(0)^{2}+(1)(9.81)(1)\\ME=0+9.81\\ME=9.81[/tex]
Hence, Mechanical Energy is 9.8 Joules (rounded to 1 decimal place). Correct answer is A.
